Process gases containing sulfur dioxide, SO2, are generated in many industrial processes. One such industrial process is combustion of a fuel such as coal, oil, peat, waste, or the like, in a combustion plant such as a power plant. In such a power plant, a hot process gas often referred to as a flue gas, is generated. The generated flue gas contains pollutants such as for example acid gases, such as for example sulfur dioxide, SO2. It is necessary to remove as much of the generated acid gases as possible from the flue gas before emitting the flue gas into ambient air. Another example of an industrial process that generates a process gas containing pollutants is electrolytic production of aluminum from alumina. In that process, a process gas or flue gas containing sulfur dioxide, SO2, is generated within venting hoods of electrolytic cells. Similarly, it is necessary to remove as much of the generated sulfur dioxide, SO2, as possible from the flue gas before emitting the flue gas into ambient air.
WO 2008/105212 discloses a boiler system comprising a boiler, a steam turbine system, and a seawater scrubber for flue gas desulfurization. The boiler generates, by combustion of a fuel, high-pressure steam utilized in the steam turbine system to generate electric power. Seawater is collected from the ocean, and is utilized as a cooling medium in a condenser of the steam turbine system. Afterward, the seawater is utilized in the seawater based flue gas desulfurization scrubber to absorb sulfur dioxide, SO2, from flue gas generated in the boiler. Sulfur dioxide, SO2, absorbed by the seawater upon contact therewith in the seawater based flue gas desulfurization scrubber forms sulfite and/or bisulfite ions. Effluent seawater from the seawater based flue gas desulfurization scrubber is forwarded to a seawater aeration basin for treatment. In the seawater aeration basin, air is bubbled through the effluent seawater forwarded from the seawater based flue gas desulfurization scrubber for oxidation of sulfite and/or bisulfite ions to sulfate ions. The sulfite and/or bisulfite ions therein are so oxidized to sulfate ions by means of oxygen gas contained in the bubbled air. The resulting inert sulfate ions in the treated effluent seawater may then be release back to the ocean.
One problem associated with effluent seawater treatment in a seawater aeration basin is foam generation on the surface of the effluent seawater. Generation of foam in seawater aeration basins requires construction of larger basins to contain not only the effluent seawater but also the generated foam. Construction of larger basins means larger capital, maintenance and operational outlays. Another problem, at the present time foam generated on the surface of the effluent seawater is typically released directly back to the ocean. However, generated foam often times carries a relatively high concentration of heavy metals unsuitable for release back to the ocean. With these problems in mind, a foam intercept system for controlling effluent seawater foam levels in effluent seawater aeration basins is needed to reduce associated capital, maintenance and/or operational expenses, and to reduce or prevent the release of heavy metals into the ocean. Likewise, a method of using a foam intercept system for controlling effluent seawater foam levels in effluent seawater aeration basins is needed to reduce associated capital, maintenance and/or operational expenses, and to reduce or prevent the release of heavy metals into the ocean.